Run on a receiver/subscriber node when the provider for that
subscription is being changed. Slonik will invoke this method
before the SUBSCRIBE_SET event propogates to the receiver
so listen paths can be updated.

begin
update sl_subscribe set sub_provider=p_sub_provider
WHERE sub_set=p_sub_set AND sub_receiver=p_sub_receiver;
if found then
perform RebuildListenEntries();
notify "_schemadoc_Restart";
end if;
return 0;
end